Sheet package, package member and printer

ABSTRACT

A sheet package which can be loaded in a sheet storage chamber ( 6 ) of a printer ( 1 ) comprises a stack of sheets ( 7 ) as print media for the printer and a package member ( 8 ) covering the exterior of the stack of sheets. The package member includes a first portion ( 53 ) covering one of upper and lower faces of the stack of sheets, a second portion ( 52 ) connecting with the first portion and covering a side face of the stack of sheets, and a third portion ( 51 ) connecting with the second portion and covering the other of the upper and lower faces of the stack of sheets. The first portion of the package member includes a first exposing portion exposing part of the stack of sheets to allow the entrance of a sheet feed roller ( 12 ) of the printer. The package member includes a second exposing portion exposing a side part of the stack of sheets facing pressing members ( 61, 64 ) provided to a side wall ( 3   b ) of the sheet storage unit of the printer parallel to a sheet feed direction so that the pressing member can press the stack of sheets against a positioning portion provided to the opposite side wall ( 3   c ) of the sheet storage unit parallel to the sheet feed direction.

TECHNICAL FIELD

The present invention relates to a package member for protecting theexterior of a stack of sheets, a sheet package including the packagemember, and a printer in which the sheet package is loaded.

BACKGROUND OF THE INVENTION

Sheet packages, allowing the loading of a whole package storing andprotecting a stack of sheets into a printer for refilling the printerwith sheets, are well known. An example of such a sheet package has beendisclosed in Japanese Patent Provisional Publication No.SHO60-97145, forexample. According to the Publication, a stack of sheets is preserved ina box-shaped package made of a material like cardboard. The package isprovided with a perforated line so that a part of the package makingcontact with a sheet feed roller can be removed. When the package isloaded in a printer, the user removes the unnecessary part from thepackage along the perforated line and sets the package directly in theprinter.

Some users of sheet packages hope to form an identification part at aprescribed position on such a package member, read information from theidentification part with a sensor of the printer when the sheet packageis loaded in the printer, and utilize the information for processesexecuted by the printer. An example of a sheet package having such aconfiguration has been disclosed in Japanese Patent ProvisionalPublication No.HEI11-91958. According to the Publication, information onthe type of sheets stored in the package member, etc. is indicated bythe identification part and the information is read out from theidentification part by the printer, by which the control of a printmechanism unit, for example, can be changed depending on the type of thesheets stored in the package member, etc.

DISCLOSURE OF THE INVENTION

However, various problems arise if the positions of the package memberand the sheets (stored in the package member) in the printer are notfixed precisely when the sheet package is loaded in the printer. Forexample, since a package described in Japanese Patent ProvisionalPublication No.SHO60-97145 is formed to be slightly larger than thesheet in order to facilitate the storing of the sheets in the package,the sheets might not be positioned at a proper sheet feed positioninside the package when the package is loaded in the printer and troublelike the so-called skewing (a sheet being fed obliquely toward the printmechanism unit) can occur. On the other hand, if the clearance betweenthe package and the stack of sheets is reduced for preventing theskewing, the storing of the sheets in the package becomes difficult.

There exists a method for preventing the skewing of sheets, in whichfeeding positions of the sheets are fixed inside the sheet storage unitof the printer. For example, as a method for the positioning of thesheets in a printing device which feeds the sheets loaded in the sheetstorage unit with a sheet feed roller one by one, a side face of thestack of sheets is pressed in one direction by a spring member providedto a side part of the sheet storage unit extending in the sheet feeddirection so as to press an entire side face of the stack of sheetsagainst an inner wall of the sheet storage unit opposite to the springmember and thereby regulate the positions of the sheets.

However, if such a spring member is placed at a prescribed position in aprinter facing a portion of the aforementioned package where anunnecessary part has been removed (i.e. a portion to make contact withthe sheet feed roller, etc.) in order to let the spring member directlypush the sheets inside the package, the spring member is able to pushonly a part of the stack of sheets on the upstream side in the sheetfeed direction. Therefore, the other part of the stack of sheets on thedownstream side in the sheet feed direction is not pushed by the springmember and not positioned at a proper position, by which the sheets canbe placed obliquely inside the package and the skewing might occur inthe sheet feed operation.

Even if a spring member is provided in order to push also the part ofthe stack of sheets on the downstream side in the sheet feed direction,the spring member can not directly position the sheets since the sideface of the part is covered with the package and the spring member canonly push the exterior of the package containing the sheets.

Further, the sheet package described in Japanese Patent ProvisionalPublication No.HEI11-91958 requires complicated work in the assembly ofthe sheet package in the manufacturing process since the package memberis in the box shape, and in the loading of the package into the printersince the user has to remove the unnecessary part from the package alongthe perforated line.

Therefore, simplification of the configuration of the package member canbe an effective approach. However, if the simplification is carried outimproperly, displacement between the top and base of the package membercan be caused by force in the sheet feed direction when the sheetpackage is loaded in the printer. Especially when a sheet is being fedfrom the package member to the printer for printing, feeding force ofthe sheet feed roller is transferred to the package member via the sheetbeing fed, causing the force in the sheet feed direction and thedisplacement between the top and base of the package member. When anidentification part (like the one in Japanese Patent ProvisionalPublication No.HEI11-91958) is formed on one of the top and base of thepackage member having the simplified configuration, the identificationpart shifts from a prescribed position in the printer, causingmisidentification of the type of sheet and malfunction of the printmechanism unit.

In regard to the above problems, the present invention has the followingadvantages. By the present invention, a sheet package, allowing easystoring of the sheets in the package member and positioning of thesheets at a proper position in a printer, is provided.

Among sheet packages allowing a stack of sheets to be loaded in aprinter together with the package member, the sheet package inaccordance with the present invention simplifies the configuration ofthe package member while preventing the displacement of the packagemember relative to the printer even in the sheet feed operation.

Further, a package member for the sheet package and a printer that isloaded with the sheet package are also provided by the presentinvention.

In accordance with an aspect of the present invention, there is provideda sheet package which can be loaded in a sheet storage unit of aprinter, comprising sheets as print media for the printer and a packagemember covering the exterior of the stack of sheets. The package memberincludes a first portion covering one of upper and lower faces of thestack of sheets, a second portion connecting with the first portion andcovering a side face of the stack of sheets, and a third portionconnecting with the second portion and covering the other of the upperand lower faces of the stack of sheets. The first portion of the packagemember includes a first exposing portion exposing part of the stack ofsheets to allow entrance of a sheet feed roller of the printer. Thepackage member includes a second exposing portion exposing a side partof the stack of sheets facing a pressing member provided to a side wallof the sheet storage unit of the printer parallel to a sheet feeddirection so that the pressing member can press the stack of sheetsagainst a positioning portion provided to the opposite side wall of thesheet storage unit parallel to the sheet feed direction. There are alsoprovided a package member for the sheet package and a printer employingthe sheet package in accordance with other aspects of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the external appearance of aprinter in accordance with an embodiment of the present invention.

FIG. 2 is a sectional side view of the printer of FIG. 1.

FIG. 3 is a perspective view of the printer of FIG. 1 showing a state inwhich a lid is opened.

FIG. 4 is a sectional side view showing a state in which a sheet packagehas been stored in a sheet storage unit of the printer of FIG. 1.

FIG. 5 is an enlarged view showing the details of a sheet separationunit and a print mechanism unit of the printer of FIG. 1.

FIG. 6 is a perspective view of a sheet package which is loaded in theprinter of FIG. 1.

FIG. 7 is a developed view of a package member forming the sheet packageof FIG. 6.

FIG. 8 is a perspective view showing the package member of FIG. 7 beingfolded and assembled into the package member shown in FIG. 6.

FIG. 9 is a perspective view showing the sheet package of FIG. 6 turnedupside down.

FIG. 10 is a sectional side view showing the loading of the sheetpackage (from which a belt-shaped member has been removed) into theprinter.

FIG. 11 is a perspective view showing a state in which the sheet packageshown in FIG. 10 has been stored in the printer.

FIG. 12 is a plan view showing a state in which guide members of theprinter are pushing edges of sheets.

FIG. 13 is a cross-sectional view taken along the line XIII-XIII shownin FIG. 12.

FIG. 14 is a sectional side view showing a state in which a sheet is fedout of the sheet package stored in the printer.

FIG. 15 is a perspective view showing a modification of the sheetpackage in which a side board is further provided for covering a sideedge of the stack of sheets extending in the sheet feed direction.

FIG. 16 is a perspective view showing another modification of the sheetpackage in which the package member has only one side board covering oneside edge of the stack of sheets extending in the sheet feed direction.

FIG. 17 is a developed view of a package member forming the sheetpackage of FIG. 15.

FIG. 18 is a partial enlarged view showing an identification part inwhich an identification mark is used for positioning the sheet packagein the printer.

FIG. 19 is a partial sectional view showing a state in which a sheetpackage having tabs in its identification part has been set in theprinter.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to the drawings, a description will be given in detail ofpreferred embodiments in accordance with the present invention.

[Composition of Printer]

First, the overall composition of a printer 1 as a thermal recordingdevice will be described referring to FIGS. 1 through 5.

FIGS. 1 and 2 are a perspective external view and a sectional side viewof the printer 1. FIG. 3 is a perspective view of the printer 1 in whichpart of a lid 10 is broken and seen through. FIG. 4 is a sectional sideview showing a state in which sheets have been set in a sheet storageunit. FIG. 5 is an enlarged sectional view showing the details of asheet separation unit and a print mechanism unit.

As shown in FIG. 1, the printer 1 is designed to be compact in size,with a rectangular shape in a plan view (capable of accommodating sheetsof approximately A6-A7 size) and a thickness of approximately 2 cm orless.

A body case 2 of the printer 1 is formed by covering the base of a frame3 with a lower cover 4 and covering part of the top of the frame 3 withan upper cover 5.

In a part of the top side of the frame 3 that is not covered with theupper cover 5, a sheet storage unit 6 is formed as shown in FIG. 2. Inthe sheet storage unit 6, a sheet package 9, storing a lot ofheat-sensitive cut sheets 7 of A6-A7 size in a package member 8, can beloaded and stored as shown in FIG. 4.

The top of the sheet storage unit 6 is covered with a lid 10 which isrotatable in a direction indicated by an arrow in FIG. 2. Incidentally,a state in which the lid 10 has been opened is shown in FIG. 3 and astate in which the lid 10 has been closed with the sheet package 9loaded in the sheet storage unit 6 is shown in FIG. 4.

At one end of the sheet storage unit 6, a pickup roller (sheet feedroller) 12, a separation block 13, etc. forming a sheet separation unit11 are placed. Beneath the upper cover 5, a thermal head 15, a platenroller 16 and a paper guide 17 forming a print mechanism unit 14(described in detail later) are placed.

As shown in FIG. 3, the sheet storage unit 6 is formed as a rectangularconcave part capable of accommodating the sheet package 9. The sheetstorage unit 6 is formed of inner side walls surrounding the sheetstorage unit 6 and a bottom face 3 d at the bottom of the sheet storageunit 6. The inner side walls of the sheet storage unit 6 include aninner wall 3 a situated on the upstream side in the direction in whichthe sheet 7 is fed by the pickup roller 12 (sheet feed direction), innerwalls 3 b and 3 c extending in the sheet feed direction, and an innerwall 13 c situated on the downstream side and forming part of theseparation block 13.

The inner wall 3 b extending in the sheet feed direction is providedwith a concave part 60, and a pressing member 61 is placed inside theconcave part 60. The pressing member 61 includes a base 62 which isrotatable around a vertical axis 62X and an arm 63 provided integrallywith the base 62 (see FIG. 12).

The base 62 is equipped with a spring 61S which applies biasing force tothe arm 63 in a direction letting the arm 63 protrude from the innerwall 3 b (direction indicated by an arrow in FIG. 3). Therefore, whenthe sheet package 9 is loaded in the sheet storage unit 6, the arm 63makes contact with side edges of the sheets 7 in the sheet package 9 andthereby presses the sheets 7 against the other inner wall 3 c of thesheet storage unit 6, by which the edges of the sheets 7 are evened upand skewing of the sheets 7 is avoided during sheet feeding.

The configuration for pressing the sheet package 9 against the innerwall 3 c (pressing member 61) is not restricted to the aboveconfiguration but can be modified in various ways.

In this embodiment, the inner wall 3 b is further provided with anotherconcave part 60 a at a position a certain distance apart from theconcave part 60, and a pressing member 64 is placed inside the concavepart 60 a. The pressing member 64 includes a base 65 which is rotatablearound a vertical axis 65X and an arm 66 provided integrally with thebase 65 (see FIG. 12).

The base 66 is equipped with a spring 64S which applies biasing force tothe arm 66 in a direction letting the arm 66 protrude from the innerwall 3 b (direction indicated by an arrow in FIG. 12). The function ofthe pressing member 64 is the same as that of the pressing member 61,and thus repeated description thereof is omitted.

As shown in FIG. 3, a reflective sensor (sensor unit) 40 is provided toa part of the bottom face 3 d beside the inner wall 3 c and in thevicinity of a corner of the sheet storage unit 6. The reflective sensor40 includes four sensors 40 a-40 d arranged in the sheet feed direction.Each sensor 40 a-40 d emits light and detects the amount of reflectedlight, by which an identification mark (identification part) 41 of thesheet package 9 (explained later) is read.

Next, the sheet separation unit 11 will be explained below. As shown inFIG. 5, the pickup roller 12, the separation block 13 and the printmechanism unit 14 are provided in the vicinity of the inner wall 13 c ofthe sheet storage unit 6. On the inner surface of the lid 10, a pressureplate 18 is supported rotatably.

A bias spring 19 is placed between the pressure plate 18 and the lid 10,which constantly exerts biasing force on the pressure plate 18 so as torotate the pressure plate 18 downward.

The sheet package 9 stores the sheets 7 which have been stacked up withtheir print surfaces (surfaces to be printed on) facing downward. Thesheets 7 are set in the sheet storage unit 6, with the lower surface ofthe lowermost one of the stacked sheets 7 exposing itself partially fromthe package member 8. When the lid 10 is closed, the pressure plate 18biased downward by the aforementioned bias spring 19 presses down afront end part of the sheets 7 (in regard to the sheet feed direction)via the package member 8 (a top board 53 which will be explained later).Consequently, the exposed part of the lowermost sheet 7 makes contactwith the pickup roller 12 and pressed by the pickup roller 12 withproper force.

The separation block 13 has a separation guide surface 13 a which istilted with respect to the sheet feed direction of the pickup roller 12.

The lowermost sheet 7 contacting the pickup roller 12 is given feedingforce by the revolving pickup roller 12. With the separation function ofthe separation guide surface 13 a of the separation block 13, only onesheet 7 at the bottom of the stacked sheets 7 is separated and sent out.

The print mechanism unit 14 will be explained below. The platen roller16 is rotatably provided next to the separation block 13, and the paperguide 17 is placed close to the exterior surface of the platen roller16.

As shown in the enlarged view of FIG. 5, the paper guide 17 is providedwith a sliding surface 17 a as a concavely curved surface along theexterior surface of the platen roller 16. Between the paper guide 17 andthe body case 2, a pressure coil spring 20 is placed so as to press thesliding surface 17 a against the exterior surface of the platen roller16.

The sheet 7 separated by the aforementioned sheet separation unit 11 isfed by the pickup roller 12 as indicated by the two-dot chain line inFIG. 5 and thereby passes under the base of the separation block 13.Thereafter, the sheet 7 is guided by a guide plate 21 and fed by theplaten roller 16 to change its direction along the platen roller 16.

Specifically, the sheet 7 is guided by the guide plate 21 and fedbeneath the platen roller 16 to a gap between the platen roller 16 andthe paper guide 17. The sheet 7, sliding between the exterior surface ofthe platen roller 16 and the sliding surface 17 a of the paper guide 17,is conveyed upward by the driving force of the revolving platen roller16 changing its feed direction by 180 degrees. By the above operation,the sheet 7 reaches the top of the platen roller 16 with its printsurface facing upward.

The thermal head 15, placed nearby the top of the platen roller 16,includes a heating element unit 15 a. The thermal head 15 is rotatablysupported by a rotation axis 15 b, by which the heating element unit 15a can contact and separate from the top of the platen roller 16.

Incidentally, the thermal head 15 is designed to be rotatable as abovein order to make a “paper jam clearance operation” possible when thesheet 7 gets jammed between the platen roller 16 and the paper guide 17.

To the thermal head 15, an end of a spring 22 of a twisting coil springtype is attached. The spring 22 constantly biases the thermal head 15 ina direction letting the heating element unit 15 a make contact with thetop of the platen roller 16.

The sheet 7 is conveyed by the platen roller 16 with its print surfacefacing upward and the print surface makes contact with the heatingelement unit 15 a of the thermal head 15, by which the printing iscarried out at the contacting part.

The thermal head 15, formed as a line head, is capable of printing anarbitrary character string or image on the conveyed heat-sensitive sheet7 in a direction orthogonal to the feed direction of the sheet 7. Theprintable width of the thermal head 15 is set approximately equal to thewidth of the sheet 7.

In this embodiment, heat-coloring sheets are employed as the sheets 7.The heat-coloring sheet includes a coloring layer (coloring when heatedby the thermal head 15) formed on its one side as an image receivinglayer.

On the separation block 13, a sheet ejection guide surface 13 b, tiltedfrom the sheet feed direction of the platen roller 16 toward the top ofthe printer 1, is formed.

The sheet 7 after being printed on by the heating element unit 15 a ofthe thermal head 15 is guided by the sheet ejection guide surface 13 band thereby ejected upward through a gap between the lid 10 and theupper cover 5 of the body case 2, as indicated by two-dot chain lines inFIG. 1.

[Composition of Sheet Package]

Next, the sheet package 9 which is set in the printer 1 in thisembodiment will be explained below.

FIG. 6 is a perspective view of the sheet package 9. As shown in FIG. 6,the sheet package 9 includes the sheets 7 as cut sheets, the packagemember 8 storing the sheets 7 which have been stacked up, and a longbelt-shaped member 70 bundling the package member 8 up.

As the sheets 7, small-sized sheets of approximately A6-A7 size areused, for example. The package member 8 stores approximately 50 sheetstherein.

The belt-shaped member 70 is wound around the package member 8 in adirection orthogonal to the sheet feed direction to bundle the packagemember 8 up. As the belt-shaped member 70, a member having a width ⅕-½of the length of the sheet 7 in the sheet feed direction is used.

The package member 8 includes a top board 53 having substantially thesame (rectangular) shape as the sheet 7, a side board 52 connecting withthe top board 53, and a base board 51 connecting with the side board 52.Specifically, out of two edges 91 and 92 of the top board 53 orthogonalto the sheet feed direction, an edge 91 on the upstream side connectswith the side board 52, and an edge 93 of the side board 52 (opposite tothe edge 91 connecting with the top board 53) connects with the baseboard 51, by which the base board 51, the side board 52 and the topboard 53 are formed integrally.

FIG. 7 is a developed view of the package member 8, in which the packagemember 8 before being folded is shown. The package member 8 shown inFIG. 6 is obtained by folding a flat cardboard material shown in FIG. 7into a shape like “U”.

The package member 8 is designed to have a dimension D1 in its widthdirection substantially equal to the width of the sheet 7. The detailswill be explained later.

The package member 8 is provided with creases. The creases 80 are formedat the boundaries between the base board 51 and the side board 52 andbetween the side board 52 and the top board 53.

The top board 53 of the package member 8 of this embodiment isconfigured so that its dimension D2 in the sheet feed direction will besubstantially equal to the distance D3 (see FIG. 4) between the innerwalls 3 a and 13 c of the sheet storage unit 6. With this configuration,when the sheet package 9 is loaded in the sheet storage unit 6, theedges 91 and 92 of the top board 53 on the upstream/downstream sides inthe sheet feed direction make contact with the inner walls 3 a and 13 crespectively as shown in FIG. 4. By the contact of the edges 91 and 92with the inner walls 3 a and 13 c, the package member 8 is positionedcorrectly in the sheet feed direction. The details will be explainedlater.

The top board 53 of the package member 8 is provided with a display part42 to be checked by the user through a display window 10 b of theprinter when the sheet package has been set in the sheet storage unit 6.On the display part 42, the type of the sheet 7 stored in the packagemember 8 (heat-sensitive paper of a normal type, heat-sensitive papercapable of gaining two colors, label paper including a label sheetformed on a strippable sheet to be peeled from the strippable sheetafter printing and used as a label that can be stuck on objects,duplicate paper allowing simultaneous printing on two sheets, etc.) isindicated by a well-known method such as printing.

Meanwhile, the base board 51 of the package member 8 is formed to beshorter than the top board 53 in the sheet feed direction so as to allowthe entrance of the pickup roller 12 into the package. The base board 51is designed to be shorter than the top board 53 by a minimum length thatis necessary for the entrance of the pickup roller 12 into the package,since setting the dimension of the base board 51 unnecessarily short canimpair the function of the package member 8 for protecting the sheets 7.

The base board 51 has the identification mark 41 at a corner of itsunder surface (opposite to the sheets 7) on the upstream side in thesheet feed direction as shown in FIG. 6. The identification mark 41 isformed by a well-known method such as printing so that theidentification mark 41 will be situated in a reading area of thereflective sensor 40 when the sheet package 9 is set in the sheetstorage unit 6.

FIG. 9 is a perspective view showing the sheet package 9 of FIG. 6turned upside down. The identification mark 41 is composed of fourrectangular indicator bits 41 a-41 d. In this embodiment, among the fourindicator bits, 0-3 bits are colored black and the remaining bits arenot colored (left in the color (white) of the foundation of the packagemember 8). Concretely, the indicator bits 41 a, 41 c and 41 d arecolored black, while the remaining bit 41 b is left white.

The above black/white pattern has been preset depending on the type ofthe sheet 7 stored in the package member 8.

[Assembly of Sheet Package]

A process for assembling the sheet package 9 will be described below.

Starting from the package member 8 in the state of FIG. 7, the sideboard 52 is vertically folded at a crease 82 to be orthogonal to thebase board 51 as shown in FIG. 8, and the top board 53 is verticallyfolded at a crease 81 to be orthogonal to the side board 52. Since thetop board 53 and the base board 51 are vertically folded relative to theside board 52, the top board 53 and the base board 51 face each otherand the package member 8 is formed into a shape like “U”.

Subsequently, the sheets 7 which have been stacked up are sandwiched andstored between the base board 51 and the top board 53 of the packagemember 8 in the U-like shape.

When the sheets 7 are stored in the package member 8, the direction ofeach sheet 7 has been preset so that the print surface (a surface to beprinted on) of each sheet 7 will face toward the base board 51. Thedirection is preset as above in order to let the print surface of eachsheet 7 face the thermal head 15 when the sheet package 9 is loaded inthe printer 1 and the sheet 7 is fed to the print mechanism unit 14.

Finally, the belt-shaped member 70 is wound around the package member 8(sandwiching and storing the sheets 7) in a direction orthogonal to thesheet feed direction to bundle the sheet package 9 up.

As above, the sheet package 9 is assembled in a relatively easy process,by which the sheet package 9 shown in FIG. 6 is completed.

In this embodiment, the above process for assembling (manufacturing) thesheet package 9 is carried out by a manufacturer. The user of theprinter 1 purchases the sheet package 9 sold in the state of FIG. 6 anduses the sheet package 9 by loading it into the printer 1.

[Loading Sheet Package in Printer]

First, the belt-shaped member 70 wound around the package member 8 isremoved.

Subsequently, the sheet package 9 is loaded into the sheet storage unit6 of the printer 1 with the base board 51 facing downward as shown inFIG. 10.

Consequently, the exposed part of the lowermost one of the sheets 7stacked up and stored in the package member 8 makes contact with the topof the pickup roller 12. Therefore, by driving and revolving the pickuproller 12, the sheet 7 can be sent out and conveyed.

Incidentally, the lid 10 of the printer 1 is designed to be opened andclosed on the downstream side in the sheet feed direction. When thesheet package 9 is loaded into the printer 1 having such composition,the sheet package 9 is generally tilted as shown in FIG. 10 with thefront end (on the upstream side in the sheet feed direction) positionedlower than the rear end.

In the sheet package 9 of this embodiment, the side board 52 of thepackage member 8 is placed on the upstream side in the sheet feeddirection, and thus the state of storage of the sheets 7 can bemaintained by the side board 52. Therefore, the sheets 7 stored in thepackage member 8 are prevented from slipping down from the packagemember 8 and being scattered about (out of carelessness of the user)when the sheet package 9 is loaded into the sheet storage unit 6.Further, the tilting of the sheet package 9 lets the edges of the sheets7 make contact with the side board 52, by which the edges of the sheets7 stacked up are evened up at a prescribed position, preventing troublelike a paper jam from occurring.

FIG. 11 shows a state in which the sheet package 9 has been completelystored in the sheet storage unit 6. In this state, the pressing member61 in the sheet storage unit 6 rotates in the direction of the arrowshown in FIG. 11 and the arm 63 pushes side edges of the sheets 7.Similarly, the guide member 64 (see FIG. 12) also rotates and the arm 66pushes edges of the sheets 7 on the same side.

FIG. 12 shows a state in which the arm 63 of the pressing member 61 andthe arm 66 of the guide member 64 are making contact with the sheets 7and letting a side face of the sheet package 9 contact the inner wall 3c of the sheet storage unit 6. FIG. 13 is a cross-sectional view takenalong the line XIII-XIII shown in FIG. 12. As shown in FIG. 12, the arms63 and 66 are pushing the edges 7 a of the sheets 7 at two positions onthe upstream side and downstream side in the sheet feed direction. Bypushing the edges 7 a of the sheets 7 at two positions, the sheets 7 canbe moved in a mass.

The dimension D1 of the package member 8 in its width direction (seeFIG. 7) is designed to be substantially equal to the width of the sheet7. Therefore, the pressing member 61 can make contact with side edges ofthe sheets 7 without being obstructed by part of the package member 8covering the exterior of the sheets 7, by which the sheets 7 can bealigned along the inner wall 3 c on the other side of the sheet storageunit 6.

Incidentally, while the dimension (D1 in FIG. 7) of the package member 8in its width direction is set substantially equal to the width of thesheet 7 in this embodiment, the dimension D1 may also be set shorterthan the width of the sheet 7. However, it is desirable to set the widthof the package member 8 equal to that of the sheet 7 since the printsurfaces of the sheets 7 can be protected securely and edges of thesheets 7 stacked up in the sheet package 9 can be evened up easily byregistering the edges of the sheet 7 with an edge of the package member8.

A state in which the lid 10 has been closed after the loading of thesheet package 9 into the sheet storage unit 6 is shown in FIGS. 4 and 5.In this state, the top board 53 of the package member 8 is situatedbetween the pressure plate 18 (for pressing the sheets 7 against thepickup roller 12) and the sheets 7.

The sheets 7 are set in the printer 1 while being stored in the sheetpackage 9. When all the sheets 7 in the sheet package 9 are used up, theuser pulls out the empty package member 8 from the sheet storage unit 6,inserts a new stack of sheets 7 into the package member 8 (made of thebase board 51, the side board 52 and the top board 53) letting the printsurfaces of the sheets 7 face toward the base board 51, and sets therefilled sheet package 9 in the printer 1, by which printing becomespossible again. It is also possible to discard the empty package member8 pulled out from the printer 1 and load a brand-new sheet package 9into the sheet storage unit 6. As above, in this embodiment, the sheets7 are loaded in the printer necessarily in the state being stored in thepackage member 8, which is advantageous in that the sheet separationfunction of the pickup roller 12 and the separation block 13 does notdeteriorate even when the printer 1 has printed on a great number ofsheets.

Here, let us consider a case where the stack of sheets 7 makes directcontact with the pressure plate 18 not via the top board 53. In thiscase, the pressure plate 18 wears off in the continuous use of theprinter 1 and the friction between the pressure plate 18 and the stackof sheets 7 decreases, by which the separation function is lost and themulti feeding (feeding two or more sheets 7 at once) is causedfrequently. In the configuration of this embodiment, the stack of sheets7 makes direct contact with the top board 53, which is replaced togetherwith the package member 8 each time when a prescribed number of sheets 7are used up. Therefore, the friction between the top board 53 and thestack of sheets 7 does not drop even in the continuous use of theprinter 1 over the years, by which an excellent separation function ismaintained consistently and sheet feed trouble (multi feeding, etc.) isprevented from occurring.

[Method for Positioning Package Member in Printer]

Next, a method for correctly positioning the package member 8 of theheet package 9 in the printer 1 (in order to let the reflective sensor40 of the printer 1 read the identification mark 41 of the packagemember 8) will be explained below.

In regard to the width direction of the sheet package 9, the dimensionD1 (see FIG. 7) of the package member 8 in the width direction is setsubstantially equal to the width of the sheet 7 as mentioned above.Therefore, the sheets 7 are pushed by the pressing members 61 and 64(provided to the inner wall 3 b of the printer 1) against the inner wall3 c on the other side, while the package member 8 is also pushed by thepressing members 61 and 64 and positioned in the sheet storage unit 6.

Meanwhile, in the lengthwise direction of the sheet package 9 (i.e. inthe sheet feed direction), the dimension D2 (see FIG. 7) of the topboard 53 of the package member 8 in the sheet feed direction is setsubstantially equal to the distance D3 (see FIG. 4) between the innerwalls 3 a and 13 c of the sheet storage unit 6. Therefore, the edges 91and 92 of the top board 53 on the upstream/downstream sides in the sheetfeed direction make contact with the inner walls 3 a and 13 c of thesheet storage unit 6 respectively, by which the package member 8 ispositioned in the sheet storage unit 6.

By the positioning of the package member 8 in the width direction and inthe sheet feed direction, the four indicator bits 41 a-41 d of theidentification mark 41 are situated in the reading areas of the fourreflective sensors 40 a-40 d respectively, by which the reflectivesensor 40 is allowed to read the black/white pattern of the indicatorbits 41 a-41 d correctly and judge the type of the sheet 7.

By the way, the sheet feed operation by the pickup roller 12 generallyinvolves the following problem. When the feeding force is applied to thelowermost sheet 7 making contact with the pickup roller 12, the packagemember 8 also receives force in the sheet feed direction due to thefriction between the lowermost sheet 7 and the base board 51.

In this embodiment, even in the sheet feed operation, the edge 92 of thetop board 53 (on the downstream side in the sheet feed direction) makescontact with the inner wall 13 c of the sheet storage unit 6, by whichthe movement of the package member 8 can be restricted against thefeeding force from the pickup roller 12. Therefore, even though the sideboard 52 or the base board 51 connecting with the top board 53 mightshift slightly in the sheet feed direction as shown in FIG. 14, theidentification mark 41 on the package member 8 can be situated within areadable range of the reflective sensor 40 of the printer 1.

In order to let the identification mark 41 on the base board 51 bepositioned at and read by the reflective sensor 40 by letting thepackage member 8 withstand the feeding force of the pickup roller 12,the difference between the dimension D2 of the top board 53 in the sheetfeed direction and the distance D3 between the inner walls 3 a and 13 cof the sheet storage unit 6 of the printer 1 has to be within apermissible range of 1.0 mm. Taking a printing error (occurring when theidentification mark 41 is printed on the package member 8), etc. intoconsideration, the dimension difference 1.0 mm is the limit valueallowing the reflective sensor 40 to read the identification mark 41.

[Modifications]

While the above description has been given of an embodiment of thepresent invention, the technical scope of the present invention is notto be restricted by the above particular illustrative embodiment.Various modifications, design changes, etc. can be made to theembodiment without departing from the scope and spirit of the presentinvention.

For example, the sheet package 9 may be composed of the sheets 7 and thepackage member 8 only, without employing the belt-shaped member 70.

By leaving out the belt-shaped member 70 from the composition of thesheet package, manufacturing cost can be reduced correspondingly.

The sheet 7 employed for the sheet package 9 may also be aheat-perforated sheet including a perforation layer (perforated by heat)as an image receiving layer stacked on a base layer. Not onlyheat-sensitive sheets but also other types of sheets (thermal transfersheets, etc.) can be used as the sheets 7.

The package member 8 may also be formed by preparing the top board 53,the side board 52 and the base board 51 separately and thereafterconnecting them together.

The base board 51 of the package member 8 may also be configuredsubstantially in the same dimension in the sheet feed direction as thetop board 53 as long as the pickup roller 12 can enter the package andfeed the sheets 7. For example, in cases where the width of the pickuproller 12 is smaller than that of the sheet 7, a cutout part having awidth allowing the entrance of the pickup roller 12 into the package maybe formed in an end part of the base board 51 in the sheet feeddirection.

The configuration of the identification mark 41 formed on the base board51 of the package member 8 is not restricted to the black/white patternof the rectangular indicator bits made by printing. The identificationmark 41 may also be configured by forming holes at proper positions ofthe package member 8 to indicate information by a pattern of thepresence/absence of holes, for example. The identification mark 41 mayalso indicate information other than the type of the sheet 7. The pointis that some information is indicated to be recognizable to a sensor ofthe printer.

It is also possible to make a cut (for the positioning) into theidentification mark 41 printed on the base board 51 of the packagemember 8 in order to securely fix the position of the sheet package 9when the sheet package 9 is set in the sheet storage unit 6.Specifically, as shown in FIG. 18(a), a cut (positioning cut) 45 in theshape of “H” may previously be made into a white part 41 b of theidentification mark 41 printed on the base board 51 of a package member8 like the one shown in FIG. 9. In the loading of the sheet package 9into the printer 1, the user folds tabs 45 a outward from the cut 45 asshown in FIG. 18(b) and securely positions the sheet package 9 in theprinter 1 by engaging the folded tabs 45 a with a part of the printer 1for a corresponding sensor 40 b of the reflective sensor 40 (see FIG.19).

With such a configuration, the positioning can be achieved by theidentification part, by which the type of the sheet package 9 (the typeof the sheet 7) can be identified correctly and the printing can becarried out properly. In this case, an opening 46 remains in the part ofthe package member 8 where the tabs 45 a were folded outward; however,the reflective sensor 40 can judge the type of the sheet 7 correctlysince the color of the sheet 7 is also white.

The printer 1 may also be configured to carry out printing with a meansother than the thermal head 15. When the printer is allowed to be alittle larger, other printing means like an ink jet printing head may beemployed, for example.

The sensor 40 of the printer 1 is not restricted to the reflectivesensor 40. Any appropriate sensor can be employed irrespective ofwhether it is of a contact type or non-contact type.

While the package member 8 in the above embodiment is composed of threeconsecutive parts (the base board 51, the side board 52 and the topboard 53), the package member 8 is not limited to such a configuration.For example, the package member 8 may further include a side board 54covering the whole side edge 7 b of the stack of sheets 7 facing theinner wall 35 of the sheet storage unit 6 of the printer 1, as shown inFIG. 15.

It is also possible to remove the side board 52 from the configurationof FIG. 15 to leave only one side board 54 covering one side edge of thesheets 7 extending in the sheet feed direction (see FIG. 16). FIG. 17 isa developed view of the package member 8 of FIG. 16. The package member8 of FIG. 16 can be formed by folding the top board 53 of the packagemember 8 of FIG. 17 in a direction indicated by an arrow in FIG. 17.

By configuring the package member 8 to let the side board 54 cover oneside edge of the stack of sheets 7 extending in the sheet feeddirection, the displacement between the top board 53 and the base board51 caused by the sheet feed operation can be reduced effectively. By thereduction of the displacement between the top board 53 and the baseboard 51, the identification mark 41 can be positioned at the reflectivesensor 40 more precisely.

Further, a colored sheet may be added between the top board 53 of thepackage member 8 and the uppermost one of the sheets 7 stacked up in thesheet package 9. The feeding of a sheet other than the sheets 7 can letthe user recognize that all the sheet 7 in the printer have been usedup.

Therefore, a wasteful sheet feed operation with no sheet 7 remaining inthe printer 1 can be avoided and deterioration of the package member 8(caused by direct contact of the revolving pickup roller 12 with thepackage member 8) can be prevented. By the prevention of thedeterioration of the package member 8, repeated use of the packagemember 8 is made possible.

INDUSTRIAL APPLICABILITY

By the present invention, a sheet package, allowing easy storing of thesheets in the package member and positioning of the sheets at a properposition in a printer, is provided.

Among sheet packages allowing a stack of sheets to be loaded in aprinter together with the package member, the sheet package inaccordance with the present invention simplifies the configuration ofthe package member while preventing the displacement of the packagemember relative to the printer even in the sheet feed operation.

Further, a package member for the sheet package and a printer that isloaded with the sheet package are also provided by the presentinvention.

1. A sheet package which can be loaded in a sheet storage unit of aprinter, comprising: a stack of sheets as print media for the printer;and a package member covering the exterior of the stack of sheets,wherein: the package member includes a first portion covering one ofupper and lower faces of the stack of sheets, a second portionconnecting with the first portion and covering a side face of the stackof sheets, and a third portion connecting with the second portion andcovering the other of the upper and lower faces of the stack of sheets,and the first portion of the package member includes a first exposingportion exposing part of the stack of sheets to allow entrance of asheet feed roller of the printer, and the package member includes asecond exposing portion exposing a side part of the stack of sheetsfacing a pressing member provided to a side wall of the sheet storageunit of the printer parallel to a sheet feed direction so that thepressing member can press the stack of sheets against a positioningportion provided to the opposite side wall of the sheet storage unitparallel to the sheet feed direction.
 2. The sheet package according toclaim 1, wherein the second portion covers a side face of the stack ofsheets on an upstream side in the sheet feed direction.
 3. The sheetpackage according to claim 1, wherein the sheets are heat-sensitivesheets.
 4. The sheet package according to claim 1, wherein a part of thepackage member covering the exterior of the stack of sheets consists ofthe first portion, the second portion and the third portion.
 5. Thesheet package according to claim 1, wherein lengths of the first portionand the third portion of the package member in a direction orthogonal tothe sheet feed direction are equal to a length of the sheet in thedirection orthogonal to the sheet feed direction.
 6. The sheet packageaccording to claim 1, wherein the first portion includes anidentification part readable to a sensor of the printer, theidentification part including: colored/uncolored parts colored/uncoloredin a prescribed color; and a positioning cut made into the uncoloredpart in order to form a tab part which can be engaged with the sensor ofthe printer.
 7. A package member covering the exterior of a stack ofsheets and being loadable in a sheet storage unit of a printer, wherein:the package member includes a first portion covering one of upper andlower faces of the stack of sheets, a second portion connecting with thefirst portion and covering a side face of the stack of sheets, and athird portion connecting with the second portion and covering the otherof the upper and lower faces of the stack of sheets, and the firstportion includes a first exposing portion exposing part of the stack ofsheets to allow entrance of a sheet feed roller of the printer, and thepackage member includes a second exposing portion exposing a side partof the stack of sheets facing a pressing member provided to a side wallof the sheet storage unit of the printer parallel to a sheet feeddirection so that the pressing member can press the stack of sheetsagainst a positioning portion provided to the opposite side wall of thesheet storage unit parallel to the sheet feed direction.
 8. A printercomprising: a sheet package including a stack of sheets as print mediaand a package member covering the exterior of the stack of sheets; asheet storage unit in which the sheet package is loaded; and a sheetfeed roller provided to a bottom of the sheet storage unit for feedingthe stacked sheets one by one, wherein: the sheet storage unit includesa positioning portion provided to its one side wall parallel to a sheetfeed direction and a pressing member provided to the opposite side wallparallel to the sheet feed direction being biased toward the one sidewall, and the package member includes a first portion covering one ofupper and lower faces of the stack of sheets, a second portionconnecting with the first portion and covering a side face of the stackof sheets on an upstream side in the sheet feed direction, and a thirdportion connecting with the second portion and covering the other of theupper and lower faces of the stack of sheets, and the first portion ofthe package member includes a first exposing portion exposing part ofthe stack of sheets to allow entrance of the sheet feed roller, and thepackage member includes a second exposing portion exposing a side partof the stack of sheets facing the pressing member so as to allowpressing by the pressing member.
 9. A sheet package which can be loadedin a sheet storage unit of a printer, comprising: a stack of sheets asprint media for the printer; and a package member covering the exteriorof the stack of sheets, wherein: the package member includes a firstportion covering one of upper and lower faces of the stack of sheets, asecond portion connecting with the first portion and covering a sideface of the stack of sheets on an upstream side in a sheet feeddirection, and a third portion connecting with the second portion andcovering the other of the upper and lower faces of the stack of sheets,and the first portion of the package member includes an identificationpart readable to a sensor unit of the printer and a configurationallowing entrance of a sheet feed roller of the printer, and the thirdportion has edge parts on its upstream side and downstream side in thesheet feed direction, the edge parts being configured to make contactwith inner surfaces of the sheet storage unit on its upstream side anddownstream side in the sheet feed direction respectively when the sheetpackage is loaded in the sheet storage unit, and the package member ispositioned in the sheet feed direction by the contact of the edge partsof the third portion with the inner surfaces of the sheet storage unit.10. The sheet package according to claim 9, wherein the first portion isformed to be shorter than the top board in the sheet feed direction inorder to allow the entrance of the sheet feed roller.
 11. The sheetpackage according to claim 9, wherein a difference between a distancebetween the inner surfaces of the sheet storage unit on the upstreamside and downstream side in the sheet feed direction and a dimension ofthe third portion in the sheet feed direction is within 1.0 mm.
 12. Thesheet package according to claim 9, wherein the side board of thepackage member covers a side face of the stack of sheets on the upstreamside in the sheet feed direction.
 13. The sheet package according toclaim 9, wherein the second portion of the package member covers a sideface of the stack of sheets extending in the sheet feed direction. 14.The sheet package according to claim 9, wherein the first portion, thesecond portion and the third portion of the package member are formedintegrally.
 15. A package member covering the exterior of a stack ofsheets and being loadable in a sheet storage unit of a printer, wherein:the package member includes a first portion covering one of upper andlower faces of the stack of sheets, a second portion connecting with thefirst portion and covering a side face of the stack of sheets on anupstream side in a sheet feed direction, and a third portion connectingwith the second portion and covering the other of the upper and lowerfaces of the stack of sheets, and the first portion includes anidentification part readable to a sensor unit of the printer and aconfiguration allowing entrance of a sheet feed roller of the printer,and the third portion has edge parts on its upstream side and downstreamside in the sheet feed direction, the edge parts being configured tomake contact with inner surfaces of the sheet storage unit on itsupstream side and downstream side in the sheet feed directionrespectively when the sheet package is loaded in the sheet storage unit,and the package member is positioned in the sheet feed direction by thecontact of the edge parts of the third portion with the inner surfacesof the sheet storage unit.
 16. A printer comprising: a sheet packageincluding a stack of sheets as print media and a package member coveringthe exterior of the stack of sheets; a sheet storage unit in which thesheet package is loaded; a sensor unit provided to a bottom of the sheetstorage unit for identifying the type of the sheets stored in the sheetpackage; and a sheet feed roller provided to the bottom of the sheetstorage unit for feeding the stacked sheets one by one, wherein: thepackage member includes a first portion covering one of upper and lowerfaces of the stack of sheets, a second portion connecting with the firstportion and covering a side face of the stack of sheets on an upstreamside in a sheet feed direction, and a third portion connecting with thesecond portion and covering the other of the upper and lower faces ofthe stack of sheets, and the first portion includes an identificationpart readable to the sensor unit and a configuration allowing entranceof the sheet feed roller, and the third portion has edge parts on itsupstream side and downstream side in the sheet feed direction, the edgeparts being configured to make contact with inner surfaces of the sheetstorage unit on its upstream side and downstream side in the sheet feeddirection respectively when the sheet package is loaded in the sheetstorage unit, and the package member is positioned in the sheet feeddirection by the contact of the edge parts of the third portion with theinner surfaces of the sheet storage unit.